Forced-draft-furnace front which is convertible for firing with coal or oil or both



Dec, 22, 1925- 1,567,001

H. A. THOMPSON FORCED DRAFT FURNACE FRONT WHICH IS CONVERTIBLE FQR FIRING WITH GOAL OR OIL OR BOTH Filed Dec. 26 19,24 2 Sheets-Sheet 1 g] Inventor E 0% Tiwmpwn u flbme w.

T WHICH Is CONVERTIBLE FOR FIRING WITH COAL OR OIL OR BOTH Dec. 22, 1925- H. A. THOMPSON FORCED DRAFT FURNACE FRON Filed Dec. 26 1924 2 Sheets-Sheet 2 oOoooooooQo Patented Dec. 22, 1925.

UNITED STATES PATENT OFFICE.

HERBERT ALEXANDER THOM'PSON, OF MORPETH, ENGLAND, ASSIGNOB OF ONE-HALF TO SVVINNEY BROTHERS LIMITED, 613 MORPETI-I, ENGLAND, A BRITISH COMPANY.

FORGED-DRAFT-FURNACE FRONT WHICH IS CONVERTIBLE FtJR FIRING WITH COAL OR OIL OR BOTH.

Application fi1ed December To all whom it may concern.

Be it known that I, HERBERT fLLEX 'tNDER Tnoarrsow, a subject of the King of Great Britain, of \Vansbeck Ironworks, Morpeth,, in the county of Northumberland, England, have invented a new and useful Improvement in or Relating to Forced-Draft-Furnace Fronts which are Convertible for F iring with Coal or Oil or Bot-h of which the following is a specification.

This invention relates to furnace fronts for forced draft furnace which are convertible for firing with coal or oil, or both coal and oil simultaneously.

The improved furnace front is of the type wherein air directors or cones with coaxial oil burners are arranged on each side of a firing opening used for coal burning.

In a furnace front of the type referred to and made according to the present inven' tion each air director or air cone (hereinafter referred to as an air directing cone) is made integral with the wing baffles.

The arch or saddle plates which extend between the front and inner or back plate of the furnace front to form an enclosed air chamber are sloped downwardly and outwardly and their outer ends are supported upon a plate extending outwardly and upwardly from the lower part of the fire opening, the last mentioned plates being preferably made integral with the casting which forms the walls of the said tire opening.

The outer or meeting ends of the said arch or saddle plates and the upwardly extending supporting plates may be curved to coincide approximately with the outer circumference of the air directing cones.

The wing baffles, the arch bafiie connecting the same, and also the baffle plate of the fire door may be suitably perforated with air holes.

Air opening may be provided in the back or inner plate of the furnace front by which air is supplied from the air chamber to the arch baflie and thence to the wing baffles.

In addition to the sloping or inclined arch or saddle plates and the upwardly extending supporting plates therefor, the dampers by which air is admitted to the ash pit from the forced draft connection may be arranged in a somewhat vertical position 26, 1924. Serial No. 758,188.

or slightly inclined to the vertical instead of being arranged horizontally as hitherto.

Fig. 1 is a front elevation with one half in section.

Fig. 2 is a sectional plan taken through the air directing cones. I

1+1g. 3 is a sectional side elevation taken on the centre line of Fig. 1.

Fig. 4 is an elevation of the upper portion of the furnace front from within the furnace.

Fig. 5 is a detail.

In the construction shown the air directing cones a are made in one casting with the hollow wing baliles 7). This arrangement reduces the number of component parts of the furnace front to a minimum.

It also allows the large openings through the air directing cones by avoiding the necessity of passing any tubular parts through the circular opening in the inner or bacl: plate 0 of the furnace front.

A suitable strengthening facing (Z is cast around the opening in the said back plate 0 to compensate for the circular opening.

The wing or side battles b are provided with air circulation holes 6 to allow of a small quantity of air circulating through for the purpose of keeping them cool and thereby avoiding local burning.

The arch or saddle plates 6 which form the seats for the louvre valves c are now made to slope downwards and outwards with a view to preventing the obstruction which occurs when the tops of the arch plates are kept flat as in some cases it caused the arch plate to come outside of the allowable external diameter of the back plate 0. The arch plates 6 are fitted in a suitable air-tight manner on ribs carried on the back plate 0 and the external or front plate 9 of the furnace front.

A separate louvre valve 6 is thus provided for each oil burner so that independent control of air is available to each air directing cone a.

The bottom or supporting plate 7'' upon which the outer ends of the arch plates 6 rest are now made of upward sloping section, as it is found that this arrangement avoids pocketing of the air currents when the same are passing through to the ashpit at it, as the angular section gives a clear flow through the ashpit air control valves Air openings j are provided in the backplate 0 for the purpose of forming air passages which lead into the hollow arch baffle 0 which is fitted over the fire opening Z. This arch baffle is provided with air distribution holes 70 for the purpose of keeping this baffle cool and preventing local burning. The ends of this arch baffle is are left open and are made of similar section to adjacent ports 6 which are provided in the side of the wing baffles 19, these ports 6 being provided to form communicating passages to allow of the air circulating through the wing baffles I; and out through the air distribution holes 7).

The holes therefore form a common admission port for air from the air chamber at to both. the arch bafie 7s and the wing baffles b.

The flanges a which are provided for the purpose of attaching the forced draft air casing trunks from the fan, are kept as low conveniently possible to give as large an air opening as can be obtained for the purpose of admitting air into the ashpits 71, through the dampers i.

This also enables the dampers i to be arranged in a somewhat vertical position between the flange or. and the angled bottom plate 7 which arrangement also enables the full area of the available opening to be utilized as a port opening instead of as previously reducing this opening by keeping the valves 6 horizontal.

The valves 1' are provided with the usual common operating lever i and a handle 2' which may be fitted either to the right or left hand valve for the common operation of the two. V

Sight holes 0 consisting of suitable plates to hold mica or other transparent material are fitted to the front plate g within the area of the air directing cones (t in order to provide means for the attendant to View the flame of the oil burner.

The coal firing door 7; may be of any type but that shown on the drawing is of. the usual hinge type, and to this is fitted a combined lighting up and sight hole door 2) which is provided with a mica plate or other transparent material to allow the attendant to view the general conditions of the flame in the centre of the furnace. The baffle plate 32 is preferably perforated as shown.

lVhen coal burning the air directing cones may be closed by means of plates 9 which will be of similar shape to the cones, these plates being provided with air distribution holes 1 for the purpose of allowing circuiation of air to pass through them for cooling purposes.

These closing plates 9 when fitted during coal burning may be conveniently retained in t. position by bolts which can be passed through the oil burner holders after the said burners have been removed.

The operation of the improved furnace fronts for oil burning is as follows Air is led from the usual casings surrounding the forced draft furnace fronts. The louvres c are opened the requisite amount to allow air to pass through the cones a surrounding the oil burners and the air ports 7' which supply air to the hollow baffles and b.

The air dampers z are opened the requisite amount by means of the common handle i which allows air to pass through into the ashpit opening it.

A lighted torch is then inserted through the lighting up door 2) and oil allowed to pass through. the oil burners when the fuel has ignited by means of the torch which has been so inserted.

These fronts give very minute control of the air supply passing to each burner and through the ashpits and owing to the avoidance of pockets and obstructions the air supply is much more regular thereby ensuring a steady flame at the burners.

The combining of the air cone (0 andthe wing baffles Z) ensures accuracy in assembly through the avoidance of additional parts and the said parts may be removed and replaced at any time by having access through the usual aspit door instead of having to dismantle the front as previously found necessary.

lVith this arrangement oil fuel can be burned in a highly efficient manner with the usual coil fire bars removed or in position, or again with the firebars in position coal and oil may be burned in conjunction so that very inferior coal may now be employed, using only a small amount of oil fuel to maintain the necessary furnace temperatures for complete combustion of such inferior coal or solid fuel.

lVhat I claim as my invention and desire to secure by Letters Patent is z- 1. A furnace front of the type referred to comprising the combination. of inner and outer plates of thefurnace front, a fire opening formed by a casting made in one with the outer and inner plates of the furnace front, hollow perforated wing baffles, air directing cones arranged on each side of the firing opening casting and made integral with the hollow perforated wing baffles, a hollow perforated arch baffle open at its ends to the wing battles, the said inner plate of the furnace front having openings leading to said arch baffle, saddle plates extending between the outer and inner plates of the furnac. front, said saddle plates being sloped outwardly and downwardly, saddle valves mounted in said saddle plates, lower plates extending between the outer and inner plates of the furnace front and sloping upwardly from the lower part of the fire opening casting, said plates meeting and supporting the ends of the saddle plates and together therewith enclosing an air chamber leading to the air directing cones and the arch baffle, oil burners mounted in the front plate and extending through said air chambers and arranged coaxially with the air directing cones.

2. A furnace front of the type referred to comprising the combination of inner and outer plates of the furnace front, a fire opening formed by a casting made in one with the outer and inner plates of the furnace front, hollow perforated wing baffles, air directing cones arranged on each side of the firing opening casting and made integral with the hollow perforated wing baffles, a hollow perforated arch baffle open at its ends to the wing baffles, the said inner plate of the furnace front having openings leading to said arch baffle, saddle plates extending between the outer and inner plates of the furnace front, said saddle plates being sloped outwardly and downwardly and curved at their outer ends to follow the curve of the air directing cones, saddle valves mounted in said saddle plates lower plates extending between the outer and inner plates of the furnace front and sloping upwardly from the lower part of the fire opening casting, said lower plates being curved at their upper ends to follow the curve of the air directing cones and arranged to meet and support the outer ends of the saddle plates, the said saddle plates and lower plates together enclosing with the outer and inner plates of the furnace front an an chamber in communication with the air directing cones, and arch baffles and the latter being in communication with the hollow ring baffles.

3. A furnace front of the type referred to comprising the combination of inner and outer plates of the furnace front, a fire opening formed by a casting made in one with the outer and inner plates of the furnace front, hollow perforated wing baffles, air directing cones arranged on each side of the firing opening casting and made integral with the hollow perforated wing baffles, a hollow perforated arch baffie open at its .ends to the wing baffles, the said inner plate of the furnace front having openings leading to said arch bat He, saddle plates extending between the outer and inner plates of the furnace front, said saddle plates being sloped outwardly and downwardly, saddle valves mounted in said saddle plates, lower plates extending between the front and inner plates of the furnace front and sloping upwardly from the lower part of the fire opening casting, said plates meeting and supporting the ends of the saddle plates and together therewith and the outer and inner plates of the furnace front enclosing an air chamber lead ing to the air directing cones and the arch bailic, oil burners mounted in the front plate and extending through said air chambers and arranged coaxially with the air directing cones, an ash pit air chamber situated in the furnace front below the firing opening and provided with air admission dampers arranged at a steep angle.

4. A furnace front of the type referred to comprising the combination of a furnace front having an air heating chamber arranged around a coal firing opening, a pair of oil burners arranged one 011 each side of the firing opening air directing cones for said oil burners, hollow wing battles made integral with said air directing cones having their inner faces perforated and their adjacent ends open, a hollow perforated arch baffle having open ends connected to the open ends of the hollow wing baflies and open at its back to the air heating chamber of the furnace front.

5. A furnace front of the type referred to comprising the combination of a furnace front having an air heating chamber arranged around a coal firing opening, a pair of oil burners arranged one 011 each side of the firing opening air directing cones for said oil burners, hollow wing bafiies made integral with said air directing cones having their inner faces perforated and their adjacent ends open, a hollow perforated arch baffle having open ends connected to the open ends of the hollow wing battles and open at its back to the air heating chamber of the furnace front, a fire opening casting in one with the outer and inner plates of. the furnace front, saddle plates extending between the front and inner plates of the furnace front, said saddle plates being sloped outwardly and downwardly, saddle valves mounted in said saddle plates, lower plates extending between the front and inner plates of the furnace front and sloping upwardly from the lower part of the fire opening casting, said plates meeting and supporting the ends of the saddle plates and together therewith enclosing an air chamber leadin g to the air directing cones and the arch bafiie, oil burners mounted in the front plate and extending through said air chambers and arranged coaxially with the air directing cones.

6. A furnace front of the type referred to comprising the combination of a furnace front having an air heating chamber arranged around a coal firing opening, a pair of oil burners arranged one on each side of the firing opening, air directing cones for said oil burners, hollow wing baffles made integral with said air directing cones having their inner faces perforated and their adjacent ends open a hollow perforated arch baffle having open ends connected to the open ends of the hollow wing bafiles and open at its back to the air heating chamber of the furnace front, a fire opening casting in one with the outer and inner plates of the furnace front, saddle plates extending between the front and inner plates of the furnace front said saddle plates being sloped outwardly and downwardly and curved at their outer ends to follow the curve of the air directing cones, saddle Valves mounted. in said saddle plates, lower plates extending between the front and inner plates of the furnace front and sloping upwardly from the lower part of the fire opening casting, said lower plates being curved at their upper ends to follow the curve of the air directing cones and arranged to meet and support the outer ends of the saddle plates, the said saddle plates and lower plates toget-her enclosing an air chamber leading to the air directing cones and the arch baflle.

HERBERT ALEXANDER THOMPSON. 

